In molecular biology, molecular beacons are oligonucleotidehybridization probes used to report the presence of specific nucleic acids in heterogenous solutions. They are hairpin shaped molecules with an internally quenched fluorophore whose fluorescenceis restored when they bind to a target nucleic acid sequence. This is a method of detecting specific nucleic acid sequences. They are useful when it is either not possible or desirable to isolate the target nucleic acid sequence from an excess of the hybridization probes. They are typically ∼25 nucleotides long. The middle 15–30 nucleotides are complementary to the target sequence, and the five nucleotides at each end are complementary to each other and not to the target DNA. At the 5′ end of the beacon a fluorophore is attached, and at the 3′ end a quencher is attached. When the molecule is not hybridized to the target sequence, fluorescence quenching occurs. After hybridization quenching is...